1. Field of the Invention
The present invention relates to a method for the control of valves for flow path control, in particular in a medical treatment machine. The present invention furthermore relates to a method for the monitoring of the then current and/or scheduled state of a plurality of valves in flow path control, in particular in a medical treatment machine, as well as to a machine, in particular a medical treatment machine, having a control for the carrying out of the corresponding methods.
The present invention in particular relates to methods for the operation of a machine in which a cassette system is used for the transport of liquids, in particular medical liquids. The present invention is used particularly advantageously in treatment machines in the field of dialysis, in particular in the field of peritoneal dialysis. Cassette systems are usually used in such treatment machines for the transport of the treatment liquids or for the carrying out of the treatment.
The present invention in particular relates to peritoneal dialysis machines such as are presented in US 2007/0112297 A1 and US 2006/0195064 A1 as well as to methods for the operation of such peritoneal dialysis machines. The full extent of the content of 2007/0112297 A1 and US 2006/0195064 A1 is hereby an integral part of the disclosure of the present application.
2. Description of the Related Art
The disposable cassettes used in such cassette systems have fluid paths and valve points via which the flow paths required for the respective treatment step can be established in the cassette. The fluid paths of the cassettes are usually formed by liquid conducting passages which have at least one flexible wall in the region of the valve points. The flexible wall can then be pressed into the liquid conducting passage by a valve actuator and so block said passage. Pneumatically actuable actuators can e.g. be used as the actuators which expand on the application of pressure to the actuator and so serve as valve tappets. Hydraulic or electric motor valve actuators can equally be used. The liquid conducting passages with the valve points are usually arranged at the disposable cassette; the valve actuators at the treatment machine. The cassettes are then inserted into the treatment machine and coupled to it so that the valve actuators at the treatment machine come into engagement with the valve points at the cassette and determine the switching state of the valves of the cassette.
Programs are usually stored in the machine control for the control of the valves and the group of valves required for the establishing of a required flow path (e.g. from a pump chamber to the patient) are controlled via said programs. A flow path is in this context understood as the connection between two sources and/or sinks which are connected by valves, e.g. the connection between a bag and a pump which is established by opening the valves disposed between the bag and the pump as well as closing valves to other component conducting connection lines. A plurality of valves are usually provided, e.g. nine or sixteen valves in known systems, via whose different control a plurality of different flow paths between the patient, the pump chambers of the cassette and different bags with liquid or for drainage can be established.
In known methods, a flow path which is e.g. required for a certain pump cycle is fixedly predetermined by the method used. In this connection, the machine knows the corresponding flow path for the method used since it is fixedly stored in the application. If the method now requires a connection from a point A to a point D, which could theoretically take place both via B and via C, this connection is previously stored in the application—e.g. via B. The application therefore does not have a free choice, but rather has a fixedly stored connection assigned to it in the present case.
A monitoring of the permitted flow path A-B-D is not necessary in this respect since only permitted and previously fixed connections are stored in the protection system. The flow paths required for a complete application are thus stored on the programming of the methods. If now a new method should be integrated into the application of the machine, the flow paths required for this must be checked as to whether they are stored in the protection system or whether they have to be stored as new, which has to result in a total check since the change between individual flow paths to be switched possibly also has to be checked for meaningfulness. A further disadvantage of the previously known systems is furthermore the change between two preset pump cycles since all the valves first have to be closed for this purpose for safety reasons. This results in an increase in wear in the valve components. The known systems are therefore inflexible and make the implementation of new methods difficult.